Week 1 Flashcards
What is a file-based system?
A file-based system is a collection of application programs that perform services for end users. Each programs defines and manages its own data.
What are problems with the file-based approach?
Separation and isolation of data
Data independence
Duplication of data
Incompatible formats
What is meant by the term, database?
A shared collection of logically related data and a description of this data, designed to meet the information needs of an organisation.
What is a Database Management System (DBMS)?
A software system that allows users to create, define, manipulate and maintain a database.
Define Data Definition Language (DDL)?
Allows database administrators or users to describe and name entities, attributes and relationships.
Define Data Manipulation Language (DML).
Provides basic data manipulation operations on the data held in the database.
What are views?
Views allow each user to have his or her own view of the database.
What are some benefits of views?
Provide powerful and flexible security
Provide a level of security
Provide a mechanism to customize the appearance of the database
What are the major components of DBMS environment?
Machine = Hardware and software Bridge = Data Human = Procedures and people
Explain the major components of the DBMS environment in further detail.
Hardware = Can be a pc to a network of computers Software = DBMS, operating system, application program, network software Procedures = Instructions and rules that should be applied to the design of the database and DBMS.
Who are the personnel involved in the DBMS environment?
Data Administrator Database Administrator Database Designers Application Programmer End Users
What are some advantages of DBMS?
Increased productivity Increased concurrency Manipulation of data Sharing of data Improved backup and recovery facilities
What are some disadvantages of DBMS?
Size
Costs
Complexity
Higher impact of failure
